This invention relates to improvements in automatic transmissions especially for motor vehicles.
In connection with the use of motor vehicles, many attempts have been made to accomplish automatic gear transmission between the engine crankshaft and the drive shaft of the vehicle, so as to avoid use of hand gear shifting. Many such transmissions have been made up of considerable numbers of parts and subject to mechanical failures due to breakdowns of individual parts so that the vehicle is out of service for a time until repaired.
The present invention provides an automatic transmission which is made of very few parts and employs fluid impeller and turbine construction in conjunction with planetary gear arrangement which is in turn controlled by the engine manifold vacuum under various load conditions. This construction makes it possible for a smaller engine to be made which can give rapid acceleration and performance at any gear ratio level so that, for example, a one hundred horsepower motor could drive a large truck.